Screw-propeller.



PATENTBD SEPT. 19', 1905.

F. A. NEWELL.

SCREW PROPELLER.

APPLICATION FILED APR.15,1905.

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FRANK A. NEWELL, OF FALLAN, MONTANA.

SCREW-PROPELLER.

Specification of Letters Patent.

Patented Sept. 19, 1905.

Application filed April 15, 1905. Serial No. 255,746.

To ctZZ whom it may concern:

Be it known that I, FRANK A. N EWELL, a citizen of the United States, residing at Fallan, in the county of Custer and State of Montana, have invented certain new and useful Im provements in Screw-Propellers, of which the following is a specification.

This invention relates in general to screwpropellers such as are used in both aerial and aquatic navigation; and its object is to reduce both the weight and diameter of the screw for any given propelling capacity.

To this end my invention consists in the construction and combination of parts forming a screw-propeller hereinafter more fully described, and particularly pointed out in the claims, reference being had to the accompanying drawings, .in which- Figure 1 is a side view of a screw-propeller according to my invention. Fig. 2 is a front end view of a screw-propeller of the same design; and Fig. 3 represents a single blade thereof in cross-section at right angles to the line of spiral of the blade, showing the shaft in end view.

This screw may have two or more blades; but I consider three blades to be the best number for general use.

The main characteristic of this invention is the hook-shaped portion 5 of each blade 7, extending outward from the usual curve which joins the front and back of two adjacent blades, such curve being shown by the dotted line 6.

8 represents the shaft of the screw, and the whole surface of each blade lies spirally around and along the shaft or central axis.

The arrows 9 indicate the direction of revolution of this screw when used as a propeller or pump or pressure-blower; but if the same screw were to be used as a water-wheel or windmill to be propelled the water or air or other propelling medium would enter the screw at the left in Fig. 1 or at the rear in Fig. 2 and the screw would be revolved in the direction opposite to the arrows 9. As a propeller this screw has its blades set scoop-v ing to gather in air or water at its circumference as well as at the front end. From that circumferential edge the blade is a warped surface extending in a tangential spiral curve toward its axis, so that the revolving of the screw tends to draw the air or water toward its axial line, and the hook-shaped guard 5 beyond that line is to prevent the air or water from being crowded outward over the back of the blade ahead. By this construction it is thought that the screw may be given very much greater rotary speed than heretofore and maintain more nearlythe theoretical propelling capacity due to its area, and particularly as a propeller in the air or as a blower for heating and ventilating purposes it'is thought that its capacity for scooping inat the circumference as well as at its front end and itshook-shaped guards to prevent the escape of compressed air except at the rear-end delivery will increase the capacity of screws of any given area and speed. If made of sheet metal, such blades, curved with the hook shaped guards and warped into the shape shown and described, will be found to possess great stifiness for any given weight.

If it be desired to form two or more blades in a single piece by casting or forging, the hub may be filled out toward or to the dotted lines 10 without materially affecting the characteristics of its operation.

- One peculiar and very valuable result of A the hook-shaped guards is that in aquatic propulsion they free the water from the bubbles of air which get caught in, thus avoiding friction and rendering the Water more compact and serviceable. The tendency to compress thewater as it is drawn centripetally into the hook-shaped guard forces the hubbles of air out over the guard, and they pass to the rear in the groove 10 in front of the guard, out of the way of the propelling-surfaces of the blades. It is thought that this hook-shaped guard greatly increases the effectiveness of the screw-propeller and that it is equally advantageous when the screw is used as a water-wheel or windmill.

Having thus fully described my invention, what I believe to be new, and desire to secure by Letters Patent, is the following:

1. In screw-propellers, two or more spiral with a hook-shaped free extension beyond I In testimony whereof I affix my signature the joint with the shaft. in presenceof two Witnesses.

2. In screw-propellers, two or more spiral T [T blades joined together on a rotary axis and FRA1\K 5 each blade provided with a hook-shaped free WVitnesses:

extension beyond the axis substantially as N. V. WALLER,

shown and described. E. GREY. 

